Investigation of 3-Dimensional Structured Anodes for Fast Charging in Lithium-Ion Batteries

Lithium-ion batteries (LIBs) with fast charging capabilities are a critical component in electric vehicles (EVs) to reduce charging times to 15 minutes or less.¹ Current research and development efforts are focused on optimizing fast charge behavior with graphitic and silicon-based anodes. However, these anode materials face challenges which include irreversible side reactions, lithium plating, and cracking caused by volumetric strain, all of which limit their fast charge behavior. As an alternative to graphite and silicon, the use of Li₄Ti₅O₁₂ (LTO) anodes in LIB cells has been discussed.^2,3 LTO is considered a zero-strain material and, furthermore, does not develop a solid-electrolyte-interphase (SEI) during electrochemical cycling. These properties help improve cycling stability and safety at high discharge rates. Although the higher nominal voltage of LTO (~1.5 V vs. Li⁺/Li) leads to lower energy density, recent research into material modification and discharge strategies that improve LTO energy density make it more attractive for fast charging.⁴ Additionally, 3-dimensional (3D) electrodes have been investigated by researchers over the last few decades to improve power density of battery cells.^5,6 In this work, we take this concept a step further and investigate the impact of 3D structural design on the fast charge performance of LTO anodes. Our objective is to determine if a re-design of electrode architecture can enable better fast charging behavior for rates up to 10C and make these LTO anodes competitive with graphite-based anodes.<br/><br/><i>Acknowledgement</i><br/>This work was funded in part by a Defense Advanced Research Projects Agency (DARPA) Young Faculty Award and Director's Fellowship under grant number D19AP00038. The views, opinions, and findings expressed in this work are those of the authors and should not be interpreted as representing the official views or policies of the Department of Defense or the U.S. Government, and no official endorsement should be inferred. This is approved for public release and distribution is unlimited.<br/><br/>(1) Vehicle Technologies Office. <i>Batteries 2021 Annual Progress Report</i>; Department of Energy, 2021.<br/>(2) Wu, Y.; Wang, W.; Ming, J.; Li, M.; Xie, L.; He, X.; Wang, J.; Liang, S.; Wu, Y. An Exploration of New Energy Storage System: High Energy Density, High Safety, and Fast Charging Lithium Ion Battery. <i>Advanced Functional Materials</i> <b>2019</b>, <i>29</i> (1), 1805978. https://doi.org/10.1002/adfm.201805978.<br/>(3) Jin, X.; Han, Y.; Zhang, Z.; Chen, Y.; Li, J.; Yang, T.; Wang, X.; Li, W.; Han, X.; Wang, Z.; Liu, X.; Jiao, H.; Ke, X.; Sui, M.; Cao, R.; Zhang, G.; Tang, Y.; Yan, P.; Jiao, S. Mesoporous Single-Crystal Lithium Titanate Enabling Fast-Charging Li-Ion Batteries. <i>Advanced Materials</i> <b>2022</b>, <i>34</i> (18), 2109356. https://doi.org/10.1002/adma.202109356.<br/>(4) Yuan, T.; Tan, Z.; Ma, C.; Yang, J.; Ma, Z.-F.; Zheng, S. Challenges of Spinel Li₄Ti₅O₁₂ for Lithium-Ion Battery Industrial Applications. <i>Advanced Energy Materials</i> <b>2017</b>, <i>7</i> (12), 1601625. https://doi.org/10.1002/aenm.201601625.<br/>(5) Cobb, C. L.; Solberg, S. E. Communication—Analysis of Thick Co-Extruded Cathodes for Higher-Energy-and-Power Lithium-Ion Batteries. <i>J. Electrochem. Soc.</i> <b>2017</b>, <i>164</i> (7), A1339–A1341. https://doi.org/10.1149/2.0101707jes.<br/>(6) Ashby, D. S.; Choi, C. S.; Edwards, M. A.; Talin, A. A.; White, H. S.; Dunn, B. S. High-Performance Solid-State Lithium-Ion Battery with Mixed 2D and 3D Electrodes. <i>ACS Appl. Energy Mater.</i> <b>2020</b>, <i>3</i> (9), 8402–8409. https://doi.org/10.1021/acsaem.0c01029.